We propose to examine the effect of various environmental factors on the physiology, metabolism, virulence, and antigenic composition of Neisseria gonorrhoeae. Through these studies we hope to achieve a better understanding of the mechanisms and factors which influence phenotypic variation in the gonococcus. Initial studies will define the effects of specific environmental parameters (pH, temperature, limiting nutrient, CO2 concentration, and dissolved O2) on the carbohydrate, protein, and nucleic acid composition of gonococci grown in continuous culture. Further studies will define the effects of these parameters and growth rate on specific cellular components (lipopolysaccharide, outer membrane proteins, pili, phospholipids, capsule, peptidoglycan). Cells grown at a constant growth rate in a chemostat will be compared to batch-grown cells with respect to the effects of the environment on specific cellular components. In vitro phenomena will be related to potential virulence factors by determining the susceptibility of gonococci to the bactericidal activity of normal human serum and phagocytosis by human polymorphonuclear leukocytes. Changes in the cellular composition will be related to alterations in the metabolism of the organism. The metabolic parameters which we expect will vary are: concentrations and ratios of NAD(H) and NADP(H); adenylate energy charge; metabolism of glucose; tricarboxylic acid cycle activity; and cytochrome composition. Factors affecting colonial type stability will also be determined. The knowledge gained from our previous studies and the experiments described herein will enable us to isolate and characterize mutants of N. honorrhoeae which are defective in cell surface components and specific cellular functions. The effects of such mutations on the virulence of the gonococcus will be assessed in the chicken embryo and guinea pig chamber models.